1. Field of the Invention
The present invention relates to a stator structure for a rotation detector, and more particularly, to a novel improvement in a stator structure for a rotation detector for obtaining a high degree of freedom in registration of a mounting ear by forming an outer periphery of a stator body to a circular shape without providing the mounting ear projecting on the outer periphery and by forming a resin-molded frame body having the mounting ear on the outer periphery by resin-molding.
2. Description of the Related Art
In general, the structures shown in FIG. 5 and FIG. 6 are conventionally employed as this type of prior art stator structure for a rotation detector.
More specifically, in FIG. 5 and FIG. 6, reference numeral 1 denotes a stator body which is of an annular shape as a whole and formed by rotating a plurality of annular stator pieces 1a by a predetermined angle for each stator piece and laminating them (hereinafter, referred to as rotating and laminating them), and the stator body 1 has a mounting ear 2 projecting in the radial direction on its outer periphery.
The mounting ear 2 is provided with a mounting hole 3 being a long hole for mounting or registration of the stator body 1 in other equipment or the like.
An inner surface of the stator body 1 is provided with a plurality of magnetic poles 4 projecting inwardly, around each of which a stator winding 6 is wound via an insulating member 5 formed on each end surface of the stator body 1 and composed of an insulating mold or an insulating plate, etc. The stator windings 6 are located in slots 7 between the respective magnetic poles 4.
Respective ends 8 of the stator windings 6 are tied up in a bundle and led out to the outside of the stator 1.
The conventional stator structure for a rotation detector is constructed as described above and therefore has the following problem.
That is, since the stator body 1 has the projecting mounting ears 2 formed integrally on its outer periphery, it is necessary to change press dies used for press working the stator pieces composing the stator body, for example, each time positions of the mounting holes on the outer periphery are changed or each time positions for arranging the mounting ears are changed, whereby preparation of many kinds of press dies causes requirement of great cost.
Moreover, when the number of slots and the number of mounting holes are not equally disposed in the stator body, it is impossible to form the stator body by rotating and laminating the stator pieces as in prior art. In short, it is impossible to rotate the stator pieces by a predetermined angle for each stator piece and laminate them so that magnetic property of a material such as magnetic permeability in the circumferential direction of each stator piece is not locally concentrated. As a result, detection accuracy of the rotation detector is lowered.